Currently, one type of projector is known in the industry, which includes a projector main body for forming image light by modulating light emitted from a light source according to image information and projecting the enlarged image light, and a reproduction device to which a recording medium is attachable for reproduction of information recorded on the recording medium. According to at least one available projector, the projector main body and the reproduction device are combined into one body as referred to in Japanese Patent Publication No. JP-A-2006-72037.
For the reproduction device, various technologies for judging types of the attached recording medium have been proposed as referred to in Japanese Patent Publication No. JP-A-9-204728. For example, a technology disclosed in the Japanese Patent Publication No. JP-A-9-204728 judges types of attached optical disk such as CD (compact disk) and DVD (digital versatile disk).
According to the projector shown in the Japanese Patent Publication No. JP-A-2006-72037, only audio data is reproduced for reproduction of information recorded on the recording medium when the attached recording medium is a recording medium used exclusively for audio (such as audio CD). In this case, light emission from the light source for forming an image (image light) is unnecessary.
Combining the technology shown in the Japanese Patent Publication No. JP-A-9-204728 with the projector shown in the Japanese Patent Publication No. JP-A-2006-72037, for example, light emission from the light source may be stopped when the attached recording medium is of the type used exclusively for audio, and light may be emitted only when the recording medium is a recording medium not for audio only but including image data (such as DVD video) based on judgment of the types of the attached recorded medium.
According to this structure, however, a user attaches a recording medium including image data to the reproduction device and starts the projector (power on), and then the light source emits light based on the judgment that the recording medium involves image data. Among other problems, this structure may require a longer time from the startup of the projector to image formation, and thus reduces the relative ease of use. Therefore, a technology capable of reducing starting time of the projector with improved ease of use is demanded.